diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst index 8e6c721d2330..b93115ab8748 100644 --- a/Documentation/filesystems/iomap/operations.rst +++ b/Documentation/filesystems/iomap/operations.rst @@ -208,7 +208,7 @@ The filesystem must arrange to `cancel such `reservations `_ because writeback will not consume the reservation. -The ``iomap_file_buffered_write_punch_delalloc`` can be called from a +The ``iomap_write_delalloc_release`` can be called from a ``->iomap_end`` function to find all the clean areas of the folios caching a fresh (``IOMAP_F_NEW``) delalloc mapping. It takes the ``invalidate_lock``. diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index b944d77a78c6..b4f742f31041 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1145,10 +1145,36 @@ static void iomap_write_delalloc_scan(struct inode *inode, } /* + * When a short write occurs, the filesystem might need to use ->iomap_end + * to remove space reservations created in ->iomap_begin. + * + * For filesystems that use delayed allocation, there can be dirty pages over + * the delalloc extent outside the range of a short write but still within the + * delalloc extent allocated for this iomap if the write raced with page + * faults. + * * Punch out all the delalloc blocks in the range given except for those that * have dirty data still pending in the page cache - those are going to be * written and so must still retain the delalloc backing for writeback. * + * The punch() callback *must* only punch delalloc extents in the range passed + * to it. It must skip over all other types of extents in the range and leave + * them completely unchanged. It must do this punch atomically with respect to + * other extent modifications. + * + * The punch() callback may be called with a folio locked to prevent writeback + * extent allocation racing at the edge of the range we are currently punching. + * The locked folio may or may not cover the range being punched, so it is not + * safe for the punch() callback to lock folios itself. + * + * Lock order is: + * + * inode->i_rwsem (shared or exclusive) + * inode->i_mapping->invalidate_lock (exclusive) + * folio_lock() + * ->punch + * internal filesystem allocation lock + * * As we are scanning the page cache for data, we don't need to reimplement the * wheel - mapping_seek_hole_data() does exactly what we need to identify the * start and end of data ranges correctly even for sub-folio block sizes. This @@ -1177,7 +1203,7 @@ static void iomap_write_delalloc_scan(struct inode *inode, * require sprinkling this code with magic "+ 1" and "- 1" arithmetic and expose * the code to subtle off-by-one bugs.... */ -static void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, +void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, loff_t end_byte, unsigned flags, struct iomap *iomap, iomap_punch_t punch) { @@ -1243,62 +1269,7 @@ static void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, out_unlock: filemap_invalidate_unlock(inode->i_mapping); } - -/* - * When a short write occurs, the filesystem may need to remove reserved space - * that was allocated in ->iomap_begin from it's ->iomap_end method. For - * filesystems that use delayed allocation, we need to punch out delalloc - * extents from the range that are not dirty in the page cache. As the write can - * race with page faults, there can be dirty pages over the delalloc extent - * outside the range of a short write but still within the delalloc extent - * allocated for this iomap. - * - * This function uses [start_byte, end_byte) intervals (i.e. open ended) to - * simplify range iterations. - * - * The punch() callback *must* only punch delalloc extents in the range passed - * to it. It must skip over all other types of extents in the range and leave - * them completely unchanged. It must do this punch atomically with respect to - * other extent modifications. - * - * The punch() callback may be called with a folio locked to prevent writeback - * extent allocation racing at the edge of the range we are currently punching. - * The locked folio may or may not cover the range being punched, so it is not - * safe for the punch() callback to lock folios itself. - * - * Lock order is: - * - * inode->i_rwsem (shared or exclusive) - * inode->i_mapping->invalidate_lock (exclusive) - * folio_lock() - * ->punch - * internal filesystem allocation lock - */ -void iomap_file_buffered_write_punch_delalloc(struct inode *inode, - loff_t pos, loff_t length, ssize_t written, unsigned flags, - struct iomap *iomap, iomap_punch_t punch) -{ - loff_t start_byte; - loff_t end_byte; - - if (iomap->type != IOMAP_DELALLOC) - return; - - /* If we didn't reserve the blocks, we're not allowed to punch them. */ - if (!(iomap->flags & IOMAP_F_NEW)) - return; - - start_byte = iomap_last_written_block(inode, pos, written); - end_byte = round_up(pos + length, i_blocksize(inode)); - - /* Nothing to do if we've written the entire delalloc extent */ - if (start_byte >= end_byte) - return; - - iomap_write_delalloc_release(inode, start_byte, end_byte, flags, iomap, - punch); -} -EXPORT_SYMBOL_GPL(iomap_file_buffered_write_punch_delalloc); +EXPORT_SYMBOL_GPL(iomap_write_delalloc_release); static loff_t iomap_unshare_iter(struct iomap_iter *iter) { diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 1e11f48814c0..30f2530b6d54 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -1227,8 +1227,20 @@ xfs_buffered_write_iomap_end( unsigned flags, struct iomap *iomap) { - iomap_file_buffered_write_punch_delalloc(inode, offset, length, written, - flags, iomap, &xfs_buffered_write_delalloc_punch); + loff_t start_byte, end_byte; + + /* If we didn't reserve the blocks, we're not allowed to punch them. */ + if (iomap->type != IOMAP_DELALLOC || !(iomap->flags & IOMAP_F_NEW)) + return 0; + + /* Nothing to do if we've written the entire delalloc extent */ + start_byte = iomap_last_written_block(inode, offset, written); + end_byte = round_up(offset + length, i_blocksize(inode)); + if (start_byte >= end_byte) + return 0; + + iomap_write_delalloc_release(inode, start_byte, end_byte, flags, iomap, + xfs_buffered_write_delalloc_punch); return 0; } diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 62253739dedc..d0420e962ffd 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -290,9 +290,9 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, typedef void (*iomap_punch_t)(struct inode *inode, loff_t offset, loff_t length, struct iomap *iomap); -void iomap_file_buffered_write_punch_delalloc(struct inode *inode, loff_t pos, - loff_t length, ssize_t written, unsigned flag, - struct iomap *iomap, iomap_punch_t punch); +void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, + loff_t end_byte, unsigned flags, struct iomap *iomap, + iomap_punch_t punch); int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, u64 start, u64 len, const struct iomap_ops *ops);